Geophysics

BACKGROUND The basic principle of vibroseis, transmitting modest power for a long duration is developed from the principle of pulse- compressive echo-ranging system and pulse compression in radar applications. To get good resolution, radar engineers needed a short pulse and to get long range, they needed high pulse energy. But increasing the power levels results in electrical flashover to occur in the equipment. They needed a method that could increase the energy without increasing the power. The solution was the long signal with modest power and with subsequent compression to a short pulse. The sonar engineers faced a similar problem. There is pressure level from a sonar transmitter that cannot be exceeded to avoid creation of cavities in the water on the face of the transmitter. Therefore, they also needed to increase the energy of their search pulse without increasing its power. The problem of a surface seismic source able to work on the roads is the same problem. We need to tra